Updated Renderer.cpp
Made use of atomic variables

In order to replace mutex-protected integer values (Performance
improvement)
Made String(char) explicit
Added ShaderUniform (Faster GetUniformLocation)
Improved Windows ClockGetMicroseconds precision
Added OpenGL::BindTexture(unit, type, id)

+ Fixed OpenGL::DeleteTexture
Made uniform caching less error-prone
Added safety range-check to VertexMapper methods
Fixed missing debug tools include
Added IntegralPow function
Added Quaternion::(Make)RotationBetween
Cleaned SubMesh code
Fixed IndexMapper with constant sequential buffer